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Title: Excitons in a mirror: Formation of “optical bilayers” using MoS{sub 2} monolayers on gold substrates

We report coupling of excitons in monolayers of molybdenum disulphide to their mirror image in an underlying gold substrate. Excitons at the direct band gap are little affected by the substrate whereas strongly bound C-excitons associated with a van-Hove singularity change drastically. On quartz substrates only one C-exciton is visible (in the blue) but on gold substrates a strong red-shifted extra resonance in the green is seen. Exciton coupling to its image leads to formation of a “mirror biexciton” with enhanced binding energy. Estimates of this energy shift in an emitter-gold system match experiments well. The absorption spectrum of MoS{sub 2} on gold thus resembles a bilayer of MoS{sub 2} which has been created by optical coupling. Additional top-mirrors produce an “optical bulk.”.
Authors:
;  [1] ; ;  [2] ; ;  [3]
  1. Nanophotonics Centre, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE (United Kingdom)
  2. Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore 138682 (Singapore)
  3. Physics and Materials Science Research Unit, University of Luxembourg, L-1511 Luxembourg (Luxembourg)
Publication Date:
OSTI Identifier:
22275529
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 19; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ABSORPTION SPECTRA; BINDING ENERGY; EXCITONS; GOLD; MIRRORS; MOLYBDENUM; MOLYBDENUM SULFIDES; OPTICAL SYSTEMS; RED SHIFT; SUBSTRATES